The present invention relates to power tools for tightening and loosening threaded connectors.
More particularly, it relates to such power tools which have engaging means for engaging the threaded connector to be tightened and loosened, a ratchet mechanism for turning the engaging means so as to turn a threaded connector engaged by the latter, and a drive which acts on the ratchet means to turn the ratchet means together with the engaging means and thereby to turn the threaded connector. Such power tools are known in the art, as disclosed for example in U.S. Pat. Nos. 5,054,047; 5,029,497; RE 33951; 5,953,966; 4,346,630; 5,953,966.
There are many applications which have different requirements to the power tools of this type. In some applications a customer requires a high torque accuracy, in other applications the customer seeks a high torque output, in further applications the customer prefers more side and overhead clearance to use a limited clearance tool. It is therefore advisable to provide a power tool which can satisfy various sometimes contradictory requirements of applications.
It is also known, for example from U.S. Pat. No. 5,953,966, the lever-ratchet mechanism and a linkage of the drive connected in the same housing, so that with each different nut size a different housing, linkage and lever mechanism is necessary, making it very expensive for the end user. In addition, by incorporation of the lever mechanism and the linkage of the drive in the same housing, the tool is not suited for other torque augmenting mechanisms, which in turn limits the tool use.
Accordingly, it is an object of the present invention to provide a power tool which can satisfy different requirements of applications.
In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in a power tool which has two interchangeable first housing units; two interchangeable second housing units, one of said two first housing units having a first axis and a cam mechanism to be turned by an outside power source, the other of said two first housing units having a cylinder-piston arrangement with a piston rod movable by fluid power, each of said [at least] two second housing units having a lever-ratchet mechanism, and different engaging means for engaging a threaded connector to be tightened or loosened and having a second axis perpendicular to said first axis; and means for interchangeably connecting one of said two second housing units to one of said two first housing units, so that upon rotating said cam mechanism of said one of said two first housing units in one direction said cam mechanism impart a movement along said first axis, and upon moving a piston of said other of said two first housing units a piston rod imparts a movement along said first axis, each of said movements along said first axis is applied to said lever-ratchet mechanism to make one end of a lever to move along said first axis and another end of said lever to turn around said second axis, and thereby when said cam is turned by an outside tool or said piston rod is moved along said first axis with fluid power, said lever-ratchet mechanism is moved forward and backward to ratchet the fastener in a single turning direction.
In the power tool in accordance with the present invention the torque augmenting means are separated from the torque output means in a disconnectable manner, so as to either add different sized torque output means for different nut sizes to the torque augmenting means or to add different torque augmenting means to a particularly sized torque output means. Therefore the cost for the end user is drastically decreased. Since one housing can be used with different other housings, a new power tool eliminates all limitations of the prior art and provides the end user with a truly universal power wrench.
The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.